Add kMDItemWhereFroms metadata attribute to downloaded files. Combine with qu...

chrome/browser/cocoa/file_metadata.mm

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/cocoa/file_metadata.h"
+
+#include <ApplicationServices/ApplicationServices.h>
+#include <Foundation/Foundation.h>
+
+#include "base/file_path.h"
+#include "base/scoped_cftyperef.h"
+#include "base/logging.h"
+#include "base/mac_util.h"
+#include "googleurl/src/gurl.h"
+
+namespace file_metadata {
+
+// As of Mac OS X 10.4 ("Tiger"), files can be tagged with metadata describing
+// various attributes.  Metadata is integrated with the system's Spotlight
+// feature and is searchable.  Ordinarily, metadata can only be set by
+// Spotlight importers, which requires that the importer own the target file.
+// However, there's an attribute intended to describe the origin of a
+// file, that can store the source URL and referrer of a downloaded file.
+// It's stored as a "com.apple.metadata:kMDItemWhereFroms" extended attribute,
+// structured as a binary1-format plist containing a list of sources.  This
+// attribute can only be populated by the downloader, not a Spotlight importer.
+// Safari on 10.4 and later populates this attribute.
+//
+// With this metadata set, you can locate downloads by performing a Spotlight
+// search for their source or referrer URLs, either from within the Spotlight
+// UI or from the command line:
+//     mdfind 'kMDItemWhereFroms == "http://releases.mozilla.org/*"'
+//
+// There is no documented API to set metadata on a file directly as of the
+// 10.5 SDK.  The MDSetItemAttribute function does exist to perform this task,
+// but it's undocumented.
+void AddOriginMetadataToFile(const FilePath& file, const GURL& source,
+                             const GURL& referrer) {
+  // There's no declaration for MDItemSetAttribute in any known public SDK.
+  // It exists in the 10.4 and 10.5 runtimes.  To play it safe, do the lookup
+  // at runtime instead of declaring it ourselves and linking against what's
+  // provided.  This has two benefits:
+  //  - If Apple relents and declares the function in a future SDK (it's
+  //    happened before), our build won't break.
+  //  - If Apple removes or renames the function in a future runtime, the
+  //    loader won't refuse to let the application launch.  Instead, we'll
+  //    silently fail to set any metadata.
+  typedef OSStatus (*MDItemSetAttribute_type)(MDItemRef, CFStringRef,
+                                              CFTypeRef);
+  static MDItemSetAttribute_type md_item_set_attribute_func = NULL;
+
+  static bool did_symbol_lookup = false;
+  if (!did_symbol_lookup) {
+    did_symbol_lookup = true;
+    CFBundleRef metadata_bundle =
+        ::CFBundleGetBundleWithIdentifier(CFSTR("com.apple.Metadata"));
+    if (!metadata_bundle)
+      return;
+
+    md_item_set_attribute_func = (MDItemSetAttribute_type)
+        CFBundleGetFunctionPointerForName(metadata_bundle,
+                                          CFSTR("MDItemSetAttribute"));
+  }
+  if (!md_item_set_attribute_func)
+    return;
+
+  NSString* file_path =
+      [NSString stringWithUTF8String:file.value().c_str()];
+  if (!file_path)
+    return;
+
+  scoped_cftyperef<MDItemRef> md_item(
+      MDItemCreate(NULL, reinterpret_cast<CFStringRef>(file_path)));
+  if (!md_item)
+    return;
+
+  // We won't put any more than 2 items into the attribute.
+  NSMutableArray* list = [NSMutableArray arrayWithCapacity:2];
+
+  // Follow Safari's lead: the first item in the list is the source URL of
+  // the downloaded file. If the referrer is known, store that, too.
+  NSString* origin_url = [NSString stringWithUTF8String:source.spec().c_str()];
+  if (origin_url)
+    [list addObject:origin_url];
+  NSString* referrer_url =
+      [NSString stringWithUTF8String:referrer.spec().c_str()];
+  if (referrer_url)
+    [list addObject:referrer_url];
+
+  md_item_set_attribute_func(md_item, kMDItemWhereFroms,
+                             reinterpret_cast<CFArrayRef>(list));
+}
+
+// The OS will automatically quarantine files due to the
+// LSFileQuarantineEnabled entry in our Info.plist, but it knows relatively
+// little about the files. We add more information about the download to
+// improve the UI shown by the OS when the users tries to open the file.
+void AddQuarantineMetadataToFile(const FilePath& file, const GURL& source,
+                                 const GURL& referrer) {
+  FSRef file_ref;
+  if (!mac_util::FSRefFromPath(file.value(), &file_ref))
+    return;
+
+  NSMutableDictionary* quarantine_properties = nil;
+  CFTypeRef quarantine_properties_base = NULL;
+  if (::LSCopyItemAttribute(&file_ref, kLSRolesAll, kLSItemQuarantineProperties,
+                            &quarantine_properties_base) == noErr) {
+    if (::CFGetTypeID(quarantine_properties_base) ==
+        ::CFDictionaryGetTypeID()) {
+      // Quarantine properties will already exist if LSFileQuarantineEnabled
+      // is on and the file doesn't match an exclusion.
+      quarantine_properties =
+          [[(NSDictionary*)quarantine_properties_base mutableCopy] autorelease];
+    } else {
+      LOG(WARNING) << "kLSItemQuarantineProperties is not a dictionary on file "
+                   << file.value();
+    }
+    ::CFRelease(quarantine_properties_base);
+  }
+
+  if (!quarantine_properties) {
+    // If there are no quarantine properties, then the file isn't quarantined
+    // (e.g., because the user has set up exclusions for certain file types).
+    // We don't want to add any metadata, because that will cause the file to
+    // be quarantined against the user's wishes.
+    return;
+  }
+
+  // kLSQuarantineAgentNameKey, kLSQuarantineAgentBundleIdentifierKey, and
+  // kLSQuarantineTimeStampKey are set for us (see LSQuarantine.h), so we only
+  // need to set the values that the OS can't infer.
+
+  if (![quarantine_properties valueForKey:(NSString*)kLSQuarantineTypeKey]) {
+    CFStringRef type = (source.SchemeIs("http") || source.SchemeIs("https"))
+                       ? kLSQuarantineTypeWebDownload
+                       : kLSQuarantineTypeOtherDownload;
+    [quarantine_properties setValue:(NSString*)type
+                             forKey:(NSString*)kLSQuarantineTypeKey];
+  }
+
+  if (![quarantine_properties
+          valueForKey:(NSString*)kLSQuarantineOriginURLKey] &&
+      referrer.is_valid()) {
+    NSString* referrer_url =
+        [NSString stringWithUTF8String:referrer.spec().c_str()];
+    [quarantine_properties setValue:referrer_url
+                             forKey:(NSString*)kLSQuarantineOriginURLKey];
+  }
+
+  if (![quarantine_properties valueForKey:(NSString*)kLSQuarantineDataURLKey] &&
+      source.is_valid()) {
+    NSString* origin_url =
+        [NSString stringWithUTF8String:source.spec().c_str()];
+    [quarantine_properties setValue:origin_url
+                             forKey:(NSString*)kLSQuarantineDataURLKey];
+  }
+
+  OSStatus os_error = ::LSSetItemAttribute(&file_ref, kLSRolesAll,
+                                           kLSItemQuarantineProperties,
+                                           quarantine_properties);
+  if (os_error != noErr) {
+    LOG(WARNING) << "Unable to set quarantine attributes on file "
+                 << file.value();
+  }
+}
+
+}  // namespace file_metadata